There has conventionally been known a driving support system which enables a driver to recognize a possibility of contact with an obstacle or a pedestrian during low-speed traveling such as moving-back or parking by monitoring the surroundings of his own vehicle through a camera to easily check dead angles of the vehicle surroundings which cannot be directly checked visually.
For this driving support system, various technologies have been proposed. An example is a rear-view camera device which arranges a camera in a car body rear part such as a rear trunk part, and displays a camera video imaged by the camera with a vehicle rear part set as an imaging direction on a display monitor of a dashboard to be viewed by the driver. Regarding this rear-view camera device, there has been available a type which overlay-displays a predicted track in a camera video according to steering angles of own vehicle front wheels so that a positional relation between a traveling direction of the own vehicle and an obstacle can be easily determined by the camera video. Conventionally, in addition to the system for visually supporting driving by displaying the camera video, there has been known a system which uses an ultrasonic sensor or the like for detecting an obstacle present around a vehicle by reflection of an ultrasonic wave to give a warning about presence of the obstacle, a positional relation between the own vehicle and the obstacle, or a distance from the own vehicle through a warning sound or a light emitted from a light emitting diode (LED).
Recently, as disclosed in Japanese Patent Application Laid-Open No. 2001-315603, a device has been proposed which uses an image synthesis technology to display a bird's-eye image looking down on an own vehicle from a virtual camera above the own vehicle, and displays a virtual object in a detection range of an obstacle detection sensor, a safe area having no obstacle according to a distance to an obstacle, or a road surface boundary of the object in this bird's-eye image. In Japanese Patent Application Laid-Open No. 2001-315603, a warning sound is issued when the obstacle is detected by the obstacle detection sensor.
However, as described above, when the bird's-eye image is displayed by combining the detection range of the obstacle detection sensor with the bird's-eye image, and the warning is simultaneously given, if the obstacle detected by the obstacle detection sensor is present in space away from a ground surface, irrespective of actual presence of the obstacle within the detection range of the obstacle detection sensor, the obstacle is displayed in a manner of not being present within the detection range of the obstacle detection sensor in the bird's-eye image, giving uncomfortable feelings.
The present invention has been proposed with the aforementioned situation in mind, and objects of the invention are to provide a device and a method for monitoring vehicle surroundings, which display, when an obstacle detection range is displayed in a view point converted image, the obstacle detection range without giving any uncomfortable feelings in a positional relation between the obstacle detection range and an obstacle.